Playing at Pebble Beach two days before the start of the AT&T Pebble Beach Pro-Am along with teammates including Buster Posey and George Kontos, Cain hit a 340-yard drive shot on No. 18 that helped the Giants beat the San Francisco 49ers as part of the Chevron Charity Shootout.
It was a shot that left many spectators buzzing and had some fans questioning whether it really happened.
For Cain, it was simply another signal that after two years of pain and problems in his pitching elbow, he is finally healthy and ready to once again be a permanent fixture in the Giants' rotation.
"I think I'm where I need to be right now," Cain said Friday on the eve of the Giants' FanFest at AT&T Park. "Everything's feeling good. It's still just fine-tuning and tweaking my rhythm and my motion and what I need to get done and not getting too frustrated with beginning. It's still early."
That hasn't always been Cain's approach. He admittedly tried to hurry back following season-ending surgery to remove bone chips and spurs in his elbow just as the 2014 pennant race was heating up.
Though Cain was back in time for the start of spring training last year, he opened on the disabled list because of a flexor tendon strain, spent another long stretch on the DL with nerve irritation in his pitching elbow and finished the season 2-4 with a career-high 5.79 ERA.
A 16-game winner in 2012 when he anchored San Francisco's rotation and led the Giants to the second of three World Series titles in a five-year span, Cain says the health issues that bogged him down are no longer a concern. He's been doing some throwing in Arizona and expects to be full-go when the Giants begin spring training next week.
"I like where he's at," San Francisco manager Bruce Bochy said. "He's in a good place right now. I don't know where he's going to pitch as far as in the rotation but I know talking to [head trainer Dave Groeschner] who's been watching him throw that he's throwing the ball very well now."
Having Cain healthy for a full season would be a boon for a pitching staff that is already shaping up to be one of the best in the majors.
A three-time All-Star who pitched the first perfect game in franchise history on June 13, 2012, Cain is most likely to wind up at the back end of the rotation as the fourth or fifth starter.
That might not be a bad thing if the 31-year-old pitcher can regain his form from a few years ago.
"The two guys that we've added are perfect for the situation, are perfect for our clubhouse," Cain said.
As for that 340-yard drive?
"It was close," Cain said. "We didn't really mark it off, we were just kind of guessing from what we had left into the hole. It was really the 5-iron that George hit next. He hit a 220-yard [shot] to get us close to the green and then we were able to seal the deal with a little par there and get a win."